Power from the pipes!

[TimG]

How the hell do you think hydro actually works. Water moving along by the force of gravity is how. Nobody said you put the turbine on a household drainpipe.

Maybe it is time for some remedial math. 1 liter/sec flowing through a drainpipe 2 meters above the ground has about 20 watts of energy that is expended falling to the ground. If 50% of the energy can be harvested (a generous assumption) you get 10W of power. Basically peanuts. There is no way it would be worth installing anything once you consider the cost of equipment, cost of labour, cost of maintenance and transmission losses. Edited February 23, 2015 by TimG

[kimmy]

You can't get something for nothing. It takes energy to pressurize the water that is sent through the pipes. If some of this energy is siphoned off to produce electricity you will have to create even more energy to pressurize the water.

The energy spent pressurizing the municipal water system is spent by the time the water has been raised to the level of my sink, toilet, or shower.

The utility company expends energy E = m*g*h filling my toilet tank each time I flush, and that amount doesn't change whether or not I am attempting to turn a mini-turbine or a Cornish Wheel or whatever as the water leaves my toilet and heads back down toward the sewage system.

For a little low-rise apartment building like the one I live in, the potential energy generation is probably minimal. But for a high-rise that has 200+ suites with some at high elevations, there's potentially a lot of energy that could be harvested. It could help offset electricity costs for building common areas.

-k

[Keepitsimple]

If you go to Fast Company's website, they make it a little clearer:

In Portland, one of the city's main pipelines now uses Lucid's pipes to make power that's sent into the grid.

....................

The pipes can't generate power in every location; they only work in places where water is naturally flowing downward with gravity (if water is being pumped, the system would waste energy). But they have another feature that can be used anywhere:

One should never pooh-pooh innovation but let's face it, this system has very limited application - and it's hard to see how the cost/benefit would be attractive.

[On Guard for Thee]

Maybe it is time for some remedial math. 1 liter/sec flowing through a drainpipe 2 meters above the ground has about 20 watts of energy that is expended falling to the ground. If 50% of the energy can be harvested (a generous assumption) you get 10W of power. Basically peanuts. There is no way it would be worth installing anything once you consider the cost of equipment, cost of labour, cost of maintenance and transmission losses.

You seem narrow mindedly restraining this to one drainpipe. I live in a city and I bet as I type there are thousands of toilets being flushed, all flowing into a big drainpipe. And guess what, every time you flush, an equal amount of water flows in to replace that water from a big supply pipe. A mini undergroud hydro system waiting to be tapped.

[TimG]

For a little low-rise apartment building like the one I live in, the potential energy generation is probably minimal. But for a high-rise that has 200+ suites with some at high elevations, there's potentially a lot of energy that could be harvested. It could help offset electricity costs for building common areas.

They design the pipes to take advantage of gravity in these tall buildings. Siphoning off power reduces pressure in the system and would likely cause malfunctions elsewhere in the building.

[TimG]

In Portland, one of the city's main pipelines now uses Lucid's pipes to make power that's sent into the grid.

IOW - it is run-of-the-river hydro where the "river" is a water main coming down from a mountain reservoir.

Hardly innovative.

Edited February 23, 2015 by TimG

[eyeball]

And hardly an idiotic scam.

[TimG]

And hardly an idiotic scam.

It also has nothing to do with harvesting power from flushing toilets.

[eyeball]

Like I said I think the article was rather poorly worded, it clearly mentioned flushing toilets which at first flush implied the system was also about the recovery of energy from the waste-water side and even if it isn't I think we've established it would clearly work there too and probably even more so.

This little squabble stems entirely from your assertion there was no benefit from this whatsoever.

[Wilber]

As I explained: the system is built to work on water pressure. If you reduce the pressure by creating electricity you screw up the system. That said, the system will have excess pressure in some places and you could siphon a small amount of power without screwing it up too badly, however, there is no way such a system would recover the costs of installing and maintaining it. The only possible outcome is a net increase in costs.

The entire concept is a scam designed to fool idiots how have no comprehension of how power systems work.

Hydro electric systems work on gravity. Since most sewer systems travel down hill, some of the energy should be recoverable. Whether it is cost effective would depend on the system. I live on the side of a mountain and there is a fair amount of energy in the water that flows to the bottom of the hill, none of it is recovered.

[jacee]

I think they're talking about water pipes, not sewer. Toilet paper would jam up the turbines.

[bush_cheney2004]

Yes....water-to-wire turbines are for water supply pipes...not sewer pipes.

http://www.forbes.com/sites/williampentland/2012/04/05/water-to-wire-turbine-produces-power-from-pipes/

[On Guard for Thee]

I think they're talking about water pipes, not sewer. Toilet paper would jam up the turbines.

Not after it sits in the sewage treatment ponds.

[TimG]

Not after it sits in the sewage treatment ponds.

Sewage treatment plants are built at the bottom of any hills so gravity will transport the sewage.

[On Guard for Thee]

Sewage treatment plants are built at the bottom of any hills so gravity will transport the sewage.

And where I live after the plant it runs downhill into the ocean. Elevation change + gravity equals energy.

[eyeball]

I think they're talking about water pipes, not sewer. Toilet paper would jam up the turbines.

I doubt that would be an issue in larger diameter higher volume lines. I suppose it might not be good if everyone flushed their toilets at the same time.

In any case water drainage pipes would make handy power generators in some applications.

[eyeball]

Speaking of a backed up clogged pipes in need of a mighty flush...

U.S. Senate Passes Hydropower Bills

“I consider hydropower to be our hardest working renewable resource and one that often gets overlooked in the clean energy debate,” Murkowski stated. “With only 3 percent of the nation’s 80,000 existing dams set up to generate electricity, hydropower is our greatest untapped potential for generating cost-effective, carbon-free energy.”

I can get behind that assuming the fish don't mind.

[Derek 2.0]

As I explained: the system is built to work on water pressure. If you reduce the pressure by creating electricity you screw up the system. That said, the system will have excess pressure in some places and you could siphon a small amount of power without screwing it up too badly, however, there is no way such a system would recover the costs of installing and maintaining it. The only possible outcome is a net increase in costs.

The entire concept is a scam designed to fool idiots how have no comprehension of how power systems work.

There are such systems already in place in communities that have digital water meters on each domestic water service.......of course, they only generate enough power to run a digital gauge....

[Derek 2.0]

There could be a practical system where the rain water is used to spin turbines to produce electricity.

Perhaps on a new installation?

But I can't see an retrofit ever being profitable.

WWWTT

That's an idea, grey/storm water would have far less solids to contend with than sanitary sewage....

[Derek 2.0]

For a little low-rise apartment building like the one I live in, the potential energy generation is probably minimal. But for a high-rise that has 200+ suites with some at high elevations, there's potentially a lot of energy that could be harvested. It could help offset electricity costs for building common areas.

-k

Not at all, any buildings over typically 3-4 stories already require booster pumps to deliver domestic water, including domestic hot water unless the mechanical room is on the roof, and even then, most will still have circulation pumps to deliver hot water in a timely manner.

Edited February 23, 2015 by Derek 2.0

[Derek 2.0]

The same o the way in. If yor tap water pressure dropped from 50 psi to 40 because the mainline was driving a turbine, would you really notice much, no. Of course you seem to be totally anti green so you will find whatever reason to keep those smokestacks belching.

City water pressure (in your mainline) is far higher than 50 psi, typically city water pressure is 100 psi and up. The water pressure inside your home will be reduced by a pressure reducing valve down to 60-50 psi, and most people would notice a 20% drop in pressure in their home, likewise, most modern appliances and plumbing fixtures wouldn't function properly with lower pressure.

[Derek 2.0]

Yes....water-to-wire turbines are for water supply pipes...not sewer pipes.

http://www.forbes.com/sites/williampentland/2012/04/05/water-to-wire-turbine-produces-power-from-pipes/

Likewise, they could be implemented on gas mains, and would probably require less maintenance then potable water supply lines, as there would be far less sediment within the lines, hence less junk to clog up any turbines......

[Mighty AC]

You can't get something for nothing. It takes energy to pressurize the water that is sent through the pipes. If some of this energy is siphoned off to produce electricity you will have to create even more energy to pressurize the water.

This is just another scam where some rent seeker is looking for free money from stupid politicians. There is no way that such a system could provide a net benefit.

You're right that the energy has to come from somewhere, but that's about it. If these turbines were placed in water mains, rather than in water towers, then you would have a point. It's not the speed of the water moving down the tower that provides pressure for peak water demand, but rather the height and volume.

It does takes more energy to pump the water up to the top of the tank than can be extracted from the falling water. So, if the sole purpose of water towers was to generate electricity it would be a net loser. However, the towers are already necessary to provide peak water demand and minimize the size of municipal water pumps. Hence, water pipe turbines simply recoup some of the electricity that must be spent anyway.

Additionally, cheap, off peak electricity is used to fill the towers up and the pipe turbines generate more expensive peak power as the towers provide pressure during the peak hours from 5 am - 9 am. Just like systems designed to capture and harness waste heat, this system provides free electricity by recouping some energy that must be used anyway.

Edited February 23, 2015 by Mighty AC

[eyeball]

The only real problem with the system is that it's green.

[On Guard for Thee]

City water pressure (in your mainline) is far higher than 50 psi, typically city water pressure is 100 psi and up. The water pressure inside your home will be reduced by a pressure reducing valve down to 60-50 psi, and most people would notice a 20% drop in pressure in their home, likewise, most modern appliances and plumbing fixtures wouldn't function properly with lower pressure.

I dont know where you live but my, and most city water runs between 45 - 60 PSI. Anything above 80 will do damage. The articles on to Portland system Ive see so far havnt yet explained how much of a drop it might or does cause. However I would suspect a city of its size might just have a few engineers kicking around who would have given this some thought.